Ipv6 over ipv4 transition method and apparatus for improving performance of control server

ABSTRACT

The present invention relates to a method and apparatus for performing IPv6 over IPv4 transition to improve performance of a control server. When an edge router selected by the control server according to a tunnel creation request of an IPv6 terminal receives a tunnel creation request message from the control server, the edge router transmits a tunnel creation response message for the received tunnel creation request message to the IPv6 terminal through the control server, and the edge router performs IPv6 over IPv4 transition through a tunnel created by the IPv6 terminal that received the tunnel creation response message so as to improve the performance of the control server. Therefore, loads of the control server occurred because all terminals set control tunnels to the control server can be prevented, and service extensibility due to the increase in the number of subscribers can be guaranteed.

TECHNICAL FIELD

The present invention relates to a server based IPv6 over IPv4transition method and apparatus, and more particularly, to a controlserver based IPv6 over IPv4 transition method and apparatus forimproving performance of the control server.

BACKGROUND ART

In general, a control server based IPv6 over IPv4 transition method is amethod (referred to as RFC 2529 and RFC 3053) of creating a controltunnel to the control server in order to enable a service terminal toregister its service in the control server and require converted addressinformation on a terminal to be communicated. An IPv6 terminal requiresan IPv4 address that can communicate with an IPv6 address of a receptionterminal (the other side) from the control server by using the createdcontrol tunnel and obtains the IPv4 address. Each terminal transmits atunnel creation request message to the control server in order toinitially create a control tunnel so as to be registered in the controlserver, so that the aforementioned information can be managed.

As conventional methods for IPv6 over IPv4 transition, there aretranslation methods and server based transition methods.

The translation method is a method in which a network address translatoris provided between two different IP version networks to enable IPv6 andIPv4 connection. In this method, address translation has to be performedon all packets, so that there is a problem of extensibility.

The server based transition (IPv6 over IPv4 transition) methods may beclassified into tunnel broker (referred to as RFC 3053), Teredo, andintra-site automatic tunnel addressing protocol (ISATAP).

The tunnel broker is a device for relaying tunnels, and a terminal in anIPv4 network creates a tunnel to a gateway between the IPv4 and IPv6networks. Here, the control tunnel is created to enable a terminal inthe IPv4 network to register its own information in a server tocommunicate with a terminal in the IPv6 network, and acquire informationto communicate with a terminal on the other side.

Next, Teredo uses a method similar to the tunnel broker method but isnot assigned officially by the Internet assigned numbers authority(LANA). However, in this method, a prefix for Teredo is definedadditionally, and a protocol is designed to include a possibility inwhich a terminal in the IPv4 network is under the network addresstranslation (NAT). However, the tunnel broker method describes a generalstructure in the RFC 3063 but is practically implemented inconsideration of address translation, so that the Teredo and the tunnelbroker method are not much different from each other. In addition, sinceTeredo can extract an IPv4 address from an IPv6 address, terminals candirectly communicate with each other without passing through a devicesuch as a Teredo relay, and this is a difference between the twomethods.

The ISATAP is an automatic tunneling method used between terminals orbetween a terminal and a router to provide communications between aterminal in an IPv4 intranet and another terminal in the same intranetor a terminal in an IPv6 public network connected to the intranet. Thismethod is a protocol that is not standardized by RFC yet but basicallyprovided in Microsoft Windows operating systems. ISATAP addresses usethe interface identifier ::0:5EFE:w.x.y.z, in which w.x.y.z is an IPv4address. The ISATAP interface identifier can be combined with any 64-bitprefix that is valid for IPv6 unicast addresses.

As described above, the ISATAP address includes IPv4 source anddestination addresses used to transmit ISATAP traffic through an IPv4network such as an IPv4-compatible address, a 6 over 4 address, and a 6to 4 address.

However, the aforementioned general IPv6 over IPv4 transition method hasproblems in that as the number of service terminals increases, thenumber of control tunnels increases, and a control server has loads oftunnel management. This is because the control server measures alifetime of each control tunnel and deletes or maintains the controltunnel after a service from a terminal is terminated. In addition, thecontrol server enables forwarding to transmit data to the terminal to becommunicated through the control tunnel. As described above, maintainingthe control tunnel and data forwarding through the control tunnel maycause degradation in performance of the control server.

DISCLOSURE OF INVENTION Technical Problem

The present invention provides an IPv6 over IPv4 transition method andapparatus for easily managing control tunnels regardless of the increasein the number of service terminals and enabling data forwarding throughthe tunnels to improve the performance of a control server and servicestability.

Technical Solution

According to an aspect of the present invention, there is provided amethod of performing IPv6 over IPv4 transition in a router connectedbetween an IPv6 terminal and a control server to improve performance ofthe control server, including steps of: receiving a tunnel creationrequest message from the control server operating on the basis of atunnel creation request of the IPv6 terminal; transmitting a tunnelcreation response message for the received tunnel creation requestmessage to the IPv6 terminal through the control server; and performingIPv6 over IPv4 transition through a tunnel created by the IPv6 terminalthat receives the tunnel creation response message.

According to another aspect of the present invention, there is provideda method of performing IPv6 over IPv4 transition in a control serverconnected between an IPv6 terminal and a plurality of routers to improveperformance of the control server, including steps of: receiving atunnel creation request message from the IPv6 terminal in an IPv4network through the IPv4 network; selecting an edge router from therouters registered in advance to create a tunnel between the edge routerand the IPv6 terminal; transmitting the tunnel creation request messageto the selected edge router; receiving a tunnel creation responsemessage corresponding to the tunnel creation request from the selectededge router and transmitting the received tunnel creation responsemessage to the IPv6 terminal; and when the tunnel creation responsemessage is received and the message is transmitted to the edge routerfrom the IPv6 terminal through the created tunnel, receiving a messagethat is IPv6 transited over IPv4 from the edge router.

According to another aspect of the present invention, there is providedan which is connected between an IPv6 terminal and a control server toperform IPv6 over IPv4 transition, including: an IPv6 terminal interfaceinterfacing with the IPv6 terminal through an IPv4 network and setting atunnel with the IPv6 terminal to transmit/receive messages; a forwardingcontroller, when the apparatus is selected as an edge router to set atunnel by the control server and receives a tunnel creation requestmessage from the control server, transmitting a tunnel creation responsemessage including information on the apparatus to the control server,and when the IPv6 terminal receives the tunnel creation response messagefrom the control server, performing IPv6 over IPv4 transition; a routingtable registering routing information included in the tunnel creationrequest message; and a control server interface interfacing with thecontrol server through IPv6 when receives a message from the IPv6terminal through the created tunnel.

Advantageous Effects

As described above, the control tunnel between the edge router selectedby the control server and the terminal is created, and the controltunnel can be easily managed regardless of the increase in the number ofservice terminals and data forwarding is possible. Therefore, loads ofthe control server occurred because all terminals set control tunnels tothe control server can be prevented, the performance of the controlserver is improved and service stability is increased, and serviceextensibility due to the increase in the number of subscribers can beguaranteed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating tunnel configuration through edge routersin a server based IPv6 over IPv4 transition system according to anembodiment of the present invention.

FIG. 2 is a view illustrating a detailed structure of the edge routeraccording to the embodiment of the present invention.

FIG. 3 is a view illustrating a process for setting a tunnel through theedge router in the server based IPv6 over IPv4 transition systemaccording to the embodiment of the present invention.

FIG. 4 is a view illustrating operations for determining a router tocreate a tunnel from a terminal performed by the control serveraccording to the embodiment of the present invention.

FIG. 5 is a view illustrating a tunnel request message transmitted fromthe control server to the router in the server based IPv6 over IPv4transition system according to the embodiment of the present invention.

FIG. 6 is a view illustrating a tunnel response message transmitted fromthe tunnel edge router to the control server in the server based IPv6over IPv4 transition system according to the embodiment of the presentinvention.

FIG. 7 is a view illustrating operations of processing control messagepackets for IPv6 over IPv4 transition according to the embodiment of thepresent invention.

FIG. 8 is a view illustrating data forwarding in the server based IPv6over IPv4 transition system according to the embodiment of the presentinvention.

FIG. 9 is a view illustrating operations of checking connection betweenthe edge router and the control server in the server based IPv6 overIPv4 transition system according to the embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Exemplary embodiments of the present invention will now be described indetail with reference to the accompanying drawings. Like referencenumerals designate like elements throughout the specification. In thedescription, the detailed descriptions of well-known functions andstructures may be omitted so as not to hinder the understanding of thepresent invention.

FIG. 1 is a view illustrating a server based IPv6 over IPv4 transitionsystem including tunnel edge routers and a server according to anembodiment of the present invention.

Referring to FIG. 1, the IPv6 over IPv4 transition system includes aplurality of terminals 101, a plurality of routers 102 for formingtunnels (referred to as IPv6 over IPv4 tunnels and hereinafter, referredto as control tunnels), and a control server 103 for selecting an edgerouter 102 for an available tunnel according to a tunnel creationrequest from a terminal 101 and transmitting/receiving messages to/fromthe terminal 101 through the selected edge router 102.

The terminal 101 is an IPv6 terminal, requests tunnel creation of thecontrol server 103, and generates a control tunnel with the router 102according to a result of the requesting.

The edge router 102 may be configured as a dual stack router that canprocess both IPv4 and IPv6 data. In addition, the edge router 102communicates with the terminal 101 that requests the tunnel creationthrough the control tunnel and performs IPv6 communication with thecontrol server 103 through the transmission control protocol (TCP) so asto transmit an IPv4/IPv6 message (tunnel creation request message). Inaddition, when the edge router 102 attempts initial connection to thecontrol server 103, the edge router 102 transmits a message Init Msg.for a registration request to the control server to inform its presenceand transmits the number of tunnels that are currently set and thenumber of tunnels that can be added to be set.

The control server 103 adds (registers) a new router as the number ofterminals 101 increases, stores information on the added router, andperiodically checks status information on the added router to perceivewhether or not the added router can be used. In addition, the controlserver 103 determines an edge router 102 that is to form a tunnel withthe terminal 101 from among a plurality of the registered routersaccording to the number of tunnels and availability.

A structure of the edge router 102 that is a device for transitingcommunications between the terminal 101 and the control server 103through the created tunnel in the IPv6 over IPv4 transition systemhaving the aforementioned configuration is described in detail withreference to FIG. 2.

FIG. 2 is a view illustrating a detailed structure of the edge routeraccording to the embodiment of the present invention.

Referring to FIG. 2, the edge router 102 may include an IPv6 terminalinterface 111, a forwarding controller 112, a routing table 113, and acontrol server interface 114.

The IPv6 terminal interface 111 interfaces with the terminal 101 throughan IPv4 network and sets a tunnel with the terminal 101 totransmit/receive messages.

The forwarding controller 112 is selected as an edge router for settinga tunnel by the control server 103 to receive a tunnel creation requestmessage from the control server 103 and generates a tunnel interface byusing information included in the tunnel creation request messagereceived from the control server 103. In addition, when the terminal 101receives a tunnel creation response message from the control server 103and creates a tunnel, the forwarding controller 112 transitscommunications (referred to as IPv6 over IPv4 transition) between theterminal 101 and the control server 103 through the created tunnel. Inaddition, the forwarding controller 112 controls IPv6 data forwarding,informs the control server 103 of its presence to create a tunnel, andtransmits its status information and information registered in therouting table 113. Here, the status information includes the number oftunnels that are currently set in the edge router 102 and the number oftunnels that can be added to be set.

The routing table 113 registers routing information (IPv4 and IPv6addresses and the like) on the tunnel interface generated by theforwarding controller 112.

The control server interface 114 performs interfacing to communicatewith the control server 103 connected through the TCP, and when receivesa message through the creased tunnel from the terminal 101, interfaceswith the control server 103 through IPv6.

Additionally, a process for setting the tunnel between the IPv6 terminaland the control server through the router will be described in detailwith reference to FIG. 3.

FIG. 3 is a view illustrating a process for setting a tunnel through arouter in the server based IPv6 over IPv4 transition system according tothe embodiment of the present invention.

Referring to FIG. 3, in operation 201, a terminal 101 transmits a tunnelcreation request message through the IPv4 network to a router 102.Accordingly, the router 102 transmits the tunnel creation requestmessage to the control server 103 through message relaying. Here, sincea control tunnel (referred to as an IPv6 over IPv4 tunnel) from theterminal 101 is not generated yet and an IPv4 message type is required,the tunnel creation request message is transmitted in the IPv4 messagetype.

In addition, in operation 202, the control server 103 that receives thetunnel creation request message stores information (NAT, Port, IPv4private address, IPv4 global address, IPv6 address, and the like) onterminals, and selects an edge router 102 of the tunnel from among aplurality of the routers to practically generate a control tunnel inconsideration of the number of current tunnels, utilization of thetunnels, and the like.

Accordingly, the edge router 102 selected in operation 203 receives thetunnel creation request message from the control server 103, and theedge router 102 selected in operation 204 transmits a tunnel creationresponse message to the control server 103. Here, the selected edgerouter 102 creates a tunnel interface by using information included inthe tunnel creation request message and registers routing information inthe routing table 113.

Accordingly, in operation 205, the edge router 102 transmits the tunnelcreation response message including the received information for tunnelcreation to the terminal 101 through the control server 103. Thereafter,in operation 206, the terminal 101 creates a control tunnel to the edgerouter 102 by using the information included in the tunnel creationresponse message. Here, the terminal 101 requests information on areception terminal to be communicated from the control server 103through the created control tunnel. In summary, the terminal 101 setsthe control tunnel with the router 102, and accordingly the router 102communicates with the control server 103 through IPv6.

The operations of the control server in the process for setting thetunnel are described in detail with reference to FIG. 4.

FIG. 4 is a view illustrating operations for determining a router tocreate a tunnel from a terminal performed by the control serveraccording to the embodiment of the present invention.

Referring to FIG. 4, in operation 301, when a new router requests to beregistered, the control server 103 adds (registers) the new router, andin operation 302, the control server 103 stores information on thenumber of tunnels set by the new router or types of available tunnelsand sets connection. By registering the new router in the control server103 as needed as the number of service terminals increases, a properrouter can be selected from among the registered routers as the edgerouter 102 to create a tunnel.

Next, when the control server 103 receives the tunnel creation requestmessage from the terminal 101 in operation 303, the control server 103retrieves edge router information stored in advance and selects an edgerouter to form a tunnel with the terminal 101 from the routers inoperation 304. Here, the control server 103 determines the number oftunnels set for each router, availability of tunnels, and an amount ofdata used for the tunnel and selects a proper router.

Thereafter, the control server 103 transmits the tunnel creation requestmessage to the selected edge router 102 to instruct to set a tunnel inoperation 305, receives a tunnel creation response message including aresult of setting the tunnel from the edge router 102 in operation 306,and transmits the received tunnel creation response message to theterminal 101 in operation 307. Here, a structure of the tunnel creationrequest message is as illustrated in FIG. 5. The tunnel creation requestmessage includes an IP header, cmd, Type, Nat, LifeTime, an IPv4 address(referred to as a care of address (CoA)) of a terminal, and a field ofan IPv6 address of a terminal, and the tunnel creation request messagefurther includes a private CoA field when the terminal belongs to CoAand Nat. Here, the cmd field represents an operation, the Type fieldrepresents a tunnel type (for example, IPv6 over IPv4 and the like), andthe NatPort represents whether the terminal belongs to Nat.

A structure of the tunnel creation response message is as illustrated inFIG. 6 and includes an IP header, cmd, result, reason, and an IPv6address field of the terminal. Here, the result field represents atunnel setting result, and the reason field represents a cause in a caseof failure.

Operations of creating a control tunnel and processing control messagepackets transceived through the created control tunnel in the IPv6 overIPv4 system are described in detail with reference to FIG. 7.

FIG. 7 is a view illustrating operations of processing control messagepackets for IPv6 over IPv4 transition according to the embodiment of thepresent invention.

Referring to FIG. 7, in operation 401, the control server 103 receives acontrol tunnel creation request message through IPv4 from the terminal101. Accordingly, in operation 402, the control server 103 transmits thecontrol tunnel creation request message to the router 102, receives acontrol tunnel creation response message from the router 102, andtransmits the control tunnel creation response message to the terminal101.

The terminal 101 receives the control tunnel response message andgenerates a control tunnel. Thereafter, in operation 405, the terminal101 requests information on a reception terminal that is to becommunicated from the control server 103 by using the created controltunnel. Here, the IPv6 over IPv4 control tunnel is used. In this case,the IPv4 header includes information including a router 102 disposed onthe edge of the tunnel as a destination, and the IPv6 header includesinformation including the control server 103 as a destination.

Accordingly, in operation 406, since the IPv4 header included in theinformation request message indicates the router 102, the router 102performs IPv6 lookup and transmits the reception terminal informationrequest message including the lookup information to the control server103. Thereafter, in operation 407, the router 102 receives a responsemessage for the information request from the control server 103.Accordingly, in operation 408, the router 102 transmits a responsemessage for the information request through the control terminal havinga destination as the terminal 101.

As described above, data forwarding between transmission/receptionterminals using the created control tunnel is as illustrated in FIG. 8.Here, since IPv6 routing information is set in the router at a point forgenerating the control tunnel, data forwarding using the control tunnelis possible. Referring to FIG. 8, a first control tunnel is createdbetween the transmission terminal 101 and the edge router 102, andpackets forwarded through the control tunnel include data in a payloadinterval, and include information on the reception terminal andinformation on the router 102 in IPv6 and IPv4 headers and in the IPv4header, respectively. In addition, a second control tunnel is createdbetween the router 102 and the reception terminal 104, and packetsforwarded through the second control tunnel include data in a payloadinterval, and include information on the reception terminal in the IPv6header and the IPv4 header.

As illustrated in FIG. 9, the router 102 and the control server 103periodically check the opposing statuses using TCP connection.

Referring to FIG. 9, in operation 501, in a case where the router 102attempts connection to the control server 103, the router 102 initiallytransmits a message Init Msg. for a registration request to the controlserver 103 to inform its presence and transmits information on thenumber of terminals that are set in the router 102 and the number oftunnels that can be added to be set. Thereafter, the control server 103checks whether or not the router 102 can be used by using the receivedinformation and transmits a registration request response messageincluding its information (address) to the router 102.

Accordingly, in operation 502 , the router 102 receives the registrationrequest response message from the control server 103 and in operation503, sets connection with the control server 103.

Thereafter, in operation 504, the router 102 receives a statusinformation request message for periodic status maintenance from thecontrol server 103, and in operation 505, the router 102 transmits astatus information response message to the control server 103.Accordingly, the control server 103 can periodically check whether ornot the router 102 is in an available status. Here, if there is noresponse within a pre-determined time, the control server 103 recognizesthat the edge router 102 it not available and does not transmit a tunnelcreation message.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the spirit and scope of thepresent invention as defined by the appended claims.

1. A method of performing IPv6 over IPv4 transition in a routerconnected between an IPv6 terminal and a control server to improveperformance of the control server, comprising steps of: receiving atunnel creation request message from the control server operating on thebasis of a tunnel creation request of the IPv6 terminal; transmitting atunnel creation response message for the received tunnel creationrequest message to the IPv6 terminal through the control server; andperforming IPv6 over IPv4 transition through a tunnel created by theIPv6 terminal that receives the tunnel creation response message.
 2. Themethod of claim 1, further comprising a step of registering routinginformation included in the tunnel creation request message in a routingtable.
 3. The method of claim 2, wherein the step of performing IPv6over IPv4 transition is performed by using the message received from theIPv6 terminal and the routing table.
 4. The method of claim 3, wherein amessage having IPv6 header information on the message received from theIPv6 terminal and an IPv4 header including information on the router isforwarded to a reception terminal.
 5. The method of claim 1, wherein theedge router is selected by analyzing status information on a pluralityof the routers by the control server.
 6. The method of claim 1, whereinthe step of performing the IPv6 over IPv4 transition comprises steps of:receiving a message including IPv6 header and IPv4 header informationfrom the IPv6 terminal through the created tunnel; and performing IPv6lookup on IPv4 header information included in the received message andtransmitting a message including the IPv6 lookup information to thecontrol server.
 7. The method of claim 1, further comprising a step ofperiodically transmitting status information on the router to thecontrol server.
 8. A method of performing IPv6 over IPv4 transition in acontrol server connected between an IPv6 terminal and a plurality ofrouters to improve performance of the control server, comprising stepsof: receiving a tunnel creation request message from the IPv6 terminalin an IPv4 network through the IPv4 network; selecting an edge routerfrom the routers registered in advance to create a tunnel between theedge router and the IPv6 terminal; transmitting the tunnel creationrequest message to the selected edge router; receiving a tunnel creationresponse message corresponding to the tunnel creation request from theselected edge router and transmitting the received tunnel creationresponse message to the IPv6 terminal; and when the tunnel creationresponse message is received and the message is transmitted to the edgerouter from the IPv6 terminal through the created tunnel, receiving amessage that is IPv6 transited over IPv4 from the edge router.
 9. Themethod of claim 8, further comprising a step of registering a routernewly added in the IPv4 network.
 10. The method of claim 9, wherein thestep of registering the newly added router comprises steps of: receivinga registration request message including status information from the newrouter; checking whether or not the new router is available by using thestatus information; setting connection with the new router by using thestatus information when the new router is in the available status;transmitting a registration response message for the registrationrequest message to the new router; and transmitting/receiving messagefor periodically checking status information on the new router.
 11. Themethod of claim 8, further comprising a step of deleting the tunnelcreated between the edge router and the IPv6 terminal after apredetermined time set in advance.
 12. The method of claim 8, whereinthe step of selecting the edge router is performed by using statusinformation on the registered routers.
 13. An apparatus which isconnected between an IPv6 terminal and a control server to perform IPv6over IPv4 transition, comprising: an IPv6 terminal interface interfacingwith the IPv6 terminal through an IPv4 network and setting a tunnel withthe IPv6 terminal to transmit/receive messages; a forwarding controller,when the apparatus is selected as an edge router to set a tunnel by thecontrol server and receives a tunnel creation request message from thecontrol server, transmitting a tunnel creation response messageincluding information on the apparatus to the control server, and whenthe IPv6 terminal receives the tunnel creation response message from thecontrol server, performing IPv6 over IPv4 transition; a routing tableregistering routing information included in the tunnel creation requestmessage; and a control server interface interfacing with the controlserver through IPv6 when receives a message from the IPv6 terminalthrough the created tunnel.
 14. The apparatus of claim 13, wherein theforwarding controller receives a message including IPv6 header and IPv4header information from the IPv6 terminal and performs IPv6 lookup onthe IPv4 header information included in the received message to transmita message including the IPv6 lookup information to the control server.15. The apparatus of claim 13, wherein the forwarding controllerperiodically transmits the status information to the control server.